【摘要】：針對深海天然氣水合物鉆探取樣鉆具結(jié)構(gòu)及工藝流程的特殊性以及所受載荷的復(fù)雜性,“天然氣水合物鉆探取芯工程樣機及配套技術(shù)”課題組開發(fā)了無擾動保壓保真取樣鉆具系統(tǒng)進行水合物的鉆探取樣。本文結(jié)合國內(nèi)外研究現(xiàn)狀,通過理論分析、數(shù)值計算的方法對取樣鉆柱的力學(xué)行為進行分析研究。首先,論文對取樣鉆柱的靜態(tài)特性進行了計算分析。忽略取樣過程中的動態(tài)因素,將取樣鉆柱所受外部載荷按照作用機理以靜力等效方式施加到結(jié)構(gòu)上,對取樣鉆柱的受力及變形特性進行了計算分析。得出最危險工況下,取樣鉆柱等效應(yīng)力最大值為266MPa,發(fā)生在鉆桿與鉆鋌連接部位的鉆桿處。論文探討分析了不同鉆壓、扭矩、波浪以及水流對取樣鉆柱靜力學(xué)特性的影響規(guī)律,得到了鉆壓以及扭矩對取樣鉆柱等效應(yīng)力影響較大、波浪以及水流對取樣鉆柱變形影響較大等結(jié)論,對鉆具設(shè)計具有一定的指導(dǎo)意義。其次,論文對取樣鉆柱的振動模態(tài)進行了計算分析,得出了鉆柱橫向、縱向以及扭轉(zhuǎn)振動的前20階振動頻率及相應(yīng)的振型;研究了不同鉆鋌長度對取樣鉆柱振動頻率的影響,計算得出不同鉆鋌長度下取樣鉆柱的前20階振動頻率值;為防止取樣鉆柱在鉆探取樣過程中發(fā)生共振,計算得到了取樣鉆柱發(fā)生共振時的臨界轉(zhuǎn)速。而后,在考慮慣性力及阻尼作用力的基礎(chǔ)上,論文對取樣鉆柱的瞬態(tài)動力學(xué)特性進行了計算分析,探討了在波浪、水流作用下以及波浪、水流與鉆壓、扭矩的聯(lián)合作用下,取樣鉆柱危險位置處節(jié)點橫向位移、縱向位移以及單元等效應(yīng)力隨時間的變化規(guī)律;得出了鉆探取樣開始階段,取樣鉆柱橫向以及縱向存在較大的振動等結(jié)論。最后,論文對取樣鉆柱的穩(wěn)定性進行了特征值屈曲分析以及非線性屈曲分析,結(jié)果表明:非線性屈曲分析更加適合于取樣鉆柱的穩(wěn)定性分析;計算分析得到了取樣鉆柱前10階屈曲臨界載荷,取樣鉆柱最大施加鉆壓不得超過60KN,對取樣工藝制定具有重要指導(dǎo)意義。
[Abstract]:In view of the particularity of the structure and technological process of sampling drill tool for deep-sea gas hydrate drilling, and the complexity of load, The "Gas Hydrate drilling coring Engineering prototype and its supporting Technology" has developed the undisturbed pressure-preserving fidelity sampling tool system for gas hydrate drilling and sampling. In this paper, the mechanical behavior of sampled drill string is studied by means of theoretical analysis and numerical calculation according to the present research situation at home and abroad. Firstly, the static characteristics of sampled drill string are calculated and analyzed. Ignoring the dynamic factors in the sampling process, the external load on the sampled drill string is applied to the structure in a static equivalent manner according to the action mechanism, and the force and deformation characteristics of the sampled drill string are calculated and analyzed. Under the most dangerous condition, the maximum equivalent stress of the sampled drill string is 266MPa, which occurs at the connecting part of the drill pipe and the drill collar. In this paper, the influence of different drilling pressure, torque, wave and current on the statics characteristics of sampled drill string is discussed and analyzed. The results show that the effect of drilling pressure and torque on the equivalent stress of sampled drill string is greater. The conclusion that wave and current have great influence on the deformation of sampled drill string has certain guiding significance for drilling tool design. Secondly, the vibration modes of the sampled drill string are calculated and analyzed, and the first 20 order vibration frequencies and corresponding vibration modes of the horizontal, longitudinal and torsional vibrations of the drill string are obtained. The influence of different drill collar length on the vibration frequency of sampled drill string is studied, and the first 20 order vibration frequency values of sampled drill string under different drill collar length are calculated. In order to prevent the resonance of the sampled drill string during drilling, the critical rotation speed of the sampled drill string is calculated. Then, on the basis of considering inertia force and damping force, the transient dynamic characteristics of sampled drill string are calculated and analyzed, and the combined action of wave, current, drilling pressure and torque is discussed. The variation of transverse displacement, longitudinal displacement and element equivalent stress with time at the dangerous position of drill string is investigated. It is concluded that there is a large vibration in the horizontal and longitudinal direction of the sampled drill string in the initial stage of drilling sampling. Finally, the stability of sampled drill string is analyzed by eigenvalue buckling analysis and nonlinear buckling analysis. The results show that the nonlinear buckling analysis is more suitable for the stability analysis of sampled drill string. The critical load of the first 10 order buckling of the sampled drill string is obtained, and the maximum applied drilling pressure of the sampled drill string is not more than 60KN, which is of great significance to the formulation of the sampling process.
【學(xué)位授予單位】：中國石油大學(xué)(華東)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：P634

【參考文獻】

相關(guān)期刊論文 前10條

1 ，

本文編號：2464274